Method and installation for producing substrate blocks

ABSTRACT

The present invention relates to a method and an installation for producing growth substrate blocks, particularly for blocks for cuttings for horticultural use, where loose substrate material is compacted in a forming chamber ( 18 ) and thus forms useable block bodies. With the present invention a compulsory moistening of the blocks with suitably heated water is performed, after which these are made ready for use almost immediately, so that an actual conditioning no longer is necessary or can be reduced considerably. The blocks can be moistened and heated from the inside to a desired temperature in a both quick and energy saving way. The moistener, which preferably is water, can contain various additives such as nutrients or the like.

The present invention relates to a method and an installation forproducing growth substrate blocks, particularly blocks for cuttings forhorticultural use, applying a known basic technique, wherein mainlyloose material from a supply of substantially loose substrate materialsuch as sphagnum is fed into a forming chamber for compacting and,subsequently, the material is removed in compacted block or string formfor the purpose of forming useable block bodies, if necessary by cuttingthe block or string formations, which have been formed.

An example of such a known basic technique is disclosed in WO 92/03914in which the loose material is sucked into the forming chamber via ahose or pipe, as the forming chamber is provided as a cylindrical piecewith a perforated wall through which air from a surrounding suctionchamber is sucked into one end of the forming chamber via a pipe/hoseconnection from the mentioned supply of material, while the opposite endof this chamber continuously is kept closed by the material whichalready has been compacted when it is sucked in and which successivelyis removed from the forming chamber precisely through the opposite endthereof.

DE 29 09 488 describes forming of sphagnum blocks in a compressionchamber where the sphagnum is transported and compressed by rotatinghelical screw means. Moisture is added to the sphagnum near the inlet bythe end of the rotating helical screw, and moistened sphagnum iscompressed and formed. In this way the sphagnum will in the beginningcomprise most of the water as droplets without moistening the sphagnum,and first after a relative long time period the sphagnum will becomemoistened. For that reason this method is ineffective in mass productionof plant blocks.

WO 01/19165 relates to a method and an apparatus for determining themoisture content of bulk material, in particular potting soil, whereinthe volume of a quantity of bulk material is determined, the weight ofthe quantity of bulk material is determined, the specific density isthen determined from the volume and the weight, and finally the moisturecontent is determined by comparison with a table. The invention furtherrelates to a method and an apparatus for preparing bulk material, inparticular potting soil, with a predetermined moisture content, whereinthe volume of a quantity of bulk material is determined, the weight ofthe quantity of bulk material is determined, and water is then added tothe quantity of bulk material until the weight associated with thedesired moisture content is obtained.

This document only concerns filling a defined amount of preparedsphagnum in a box. If the sphagnum is dry, water is added to a mixingprocess in order to reach correct water content in the preparedsphagnum.

In order for the fed material to be handled with a mere minimum of easeit is imperative that it is provided in a loose and therefore relativelydry form, as a wet sphagnum mass is much more difficult and thereby muchmore expensive to form into suitable shapes. On the other hand, withregard to the practical use of the block bodies it is absolutelyimperative that the blocks are provided in a practically soakedcondition at a temperature of about 18–25° C. In praxis this is done byplacing the automatically produced substrate blocks, which are providedto relevant horticultures in a very large number, on greenhouse tableswith bilge-water coverage, thus enabling the blocks partly to absorb thebilge-water and partly to assume the desired higher temperature from theheated greenhouse atmosphere.

This praxis is connected with considerable costs which according to thepresent invention can be reduced significantly by providing a compulsorymoistening of the blocks with an appropriately heated moistener, such aswater or wet steam, in immediate connection to the introduction of theblocks to the greenhouse system, preferably by establishing an infeedand treatment station from which the blocks successively are fed to thegreenhouse in a number of rows, which possibly could pass an in-linemounting area for the cuttings in the blocks, so that these subsequentlyare transported directly to the regular grow area(s) for the cuttings.

As the block bodies are fairly tightly compacted they are both slowlywater absorbent and poorly heat conducting and this is why, according tothe usual practise, it is necessary to utilise greenhouse space for theabove mentioned conditioning of the blocks, typically over a 1–2 dayperiod. As the number of blocks may reach as high as tens of thousands,a rather large greenhouse area must, thus, be reserved for this purposeand the supplied heat energy is relatively poorly utilised.

The scope of the invention is to achieve a fast and effectivepreparation and moistening of blocks for cuttings, forming a high numberof cutting blocks pr. hour for industrial greenhouse facilities.

This can be achieved with the present invention as a compulsorymoistening of the blocks with suitably moisture medium heated water, forexample by injecting the warmed water into the blocks, makes these readyfor use almost immediately, so that the special conditioning area nolonger is necessary or can be reduced to a short passage. The blocks areboth moistened and heated from the inside, so that a moistening processto a desired temperature can take place both quickly and with a minimumof heating energy. Furthermore, the moistener, which preferably iswater, can contain various additives such as nutrients and the like.

Another significant circumstance is the fact that in the indicatedproduction line it will be possible to shape the block bodies with atraditional prick opening for easy receipt of the cuttings after theblock has been largely wetted. Usually, these prick openings areperformed in the mechanical installation for the shaping of the blocksand it is a well-known observation that these prick openings are more orless closed when the cutting are received, which to a large degreecounteracts an easy mounting of the cuttings which are relativelyfragile.

In connection with the present invention a significant side effect fromperforming the prick opening as a final operation in shaping of theblock and/or moistening unit has appeared, as it has been found that theprick openings remain intact or open when provided in the alreadymoistened block bodies, even if the moistening is not yet totallyhomogeneous. When the moistening merely has advanced noticeably, theremaining swelling of the block material will not have a closing effectof the prick openings and the cuttings will, thus, be so easy to mountthat the manual mounting is considerably relieved and, thus, it is to awide extent possible to speculate in devices for an automatic mountingof cuttings in said prick openings.

The starting point of the present invention is that it has been foundpossible to simply and quickly evoke a sufficient moistening of theblock material, namely when this takes place in direct continuation ofthe shaping of the block material as such. It is still imperative thatthe fed material is loose and relatively dry, but once the material hasbeen compacted it is easily handled when removed in block or string formin wet condition.

Therefore according to the present invention it is possible that amoistener can be fed to the material in the compacting area during theshaping process, while the material still is loose and willingly ismoistened during its movement towards the compacting area and where themoistener in connection with the infeed is distributed in the formingchamber by underpressure.

Another observation is the fact that water is fed continuously to the“rear end area” of the block or block string which is being shaped, sothat every cross section hereof is subjected to active moistening. Theshaping must take place with a distinct speed, but the material issuited for maintaining infed excess water, which, subsequently, is givenmore time to be absorbed in the material by capillary effect.

In a preferred method of producing the blocks, confer for example withthe above mentioned WO document, a width of air permeable paper is addedto the infeed of the loose material, whereby said paper is continuouslyrounded up in order to created an outer holster around the producedblocks as these are cut off from the formed string. The paper widthwill, thus, surround the passage where the loose material is conveyed tothe forming chamber and it will, typically, be near the inner end ofthis passage that the water is preferably introduced. This is hardlydoable through the paper casing, but it has been found fully realisticto convey the water through a pipe or a hose which has been led into thematerial infeed opening before the infeed area for the paper casing andwhich extends towards the inside area at the infeed of the formingchamber. There is no need for any special centring or fastening of thiswater infeed when this ends shortly before the forming chamber, as theinfed material thus still can be distributed fairly evenly across thecross section of the formed block material, even though the depositedmaterial now is significantly water carrying.

However, it must be mentioned that is has been found particularlyadvantageous to arrange the water supply via a freely hanging hose inconnection with a vertical inwardly directed infeed of the infeedmaterial to the forming chamber, which equally can be verticallyoriented with the inherent advantage that the removed block material canbe led directly into receiving cells in underlying, horizontallyconveyed mounting trays for delivery to the greenhouse. Thus, is willalso be increasingly possible to use particular additives such asperlite or clay as the blocks are erect in their surrounding papercasing during the entire process.

The loose infeed material will often be colder than the greenhousetemperature and in this case it will be relevant to use extra heatedwater, for example at 60-70° C., in order to quickly achieve the desiredtemperature in the wet blocks. At this or at even higher temperatures athermal sterilising effect on the material can be achieved and as thematerial is led directly to the greenhouse, the used heat energy will beregained via the transfer of heat to the air. Furthermore, the moistenercan contain additives, which cause a chemical sterilisation of thematerial.

The entire process can take place practically without any waste ofwater, which is of great importance for an effective utilisation ofvarious additives to the water.

The shaping of the above mentioned prick openings (“pricking out holes”)can take place using already known means in the form of a double pistonwhich is rested against the top of the block, after which the gudgeonpin is activated for a quick down and up shooting in order to form thehole. This technique is fully useable regardless of the fact that theblocks are decidedly wet and, as mentioned, is has been found that theholes in the wet material furthermore are particularly form stabile.

While the starting point of the invention is the successive moisteningof the block material during the shaping of the blocks, the derivedimmediate infeed of the blocks to the greenhouse has shown such greatadvantages that the invention also will cover this aspect, regardless ofwhether other methods of moistening are used, for example injection ofwater or wet steam or a forced application of such in the already shapedblocks. The shaping of the blocks per se will thus not be confined totake place in connection to the greenhouse installation.

In the following the invention is described with reference to thedrawing which, without being limiting, indicates a preferred embodimentof an installation for producing growth substrate blocks according tothe invention where:

FIG. 1 is a situation drawing of an entire installation,

FIG. 2 is a partial drawing indicating the area around the formingchamber and

FIG. 3 shows the arrangement of infeed hose/pipe for the moistener.

In FIG. 1 is shown an entire installation for producing moistened growthsubstrate blocks. The installation comprises a fully automatic substratepotting machine 2, a pricking out machine 4 and a transfer unit 6, allconnected to a system of conveyer belts 8. From the transfer unit 6 thesubstrate blocks, which are placed in trays 10, are conveyed to agreenhouse table 12. In an alternative embodiment not shown a furthermachine for automatic placement of cuttings is comprised.

As can be seen in FIG. 1 a width 16 of air permeable paper is led from areel 14 to the forming section as such. This paper width 16 is formed toan “endless tube”, which via vacuum is filled with substrate in theforming chamber 18. Prior to the area where said paper width 16 isjoined to a tube, a hose 20 or a pipe is led into the infeed 22 for thesubstrate material. Through this hose/pipe 20 the moistener in the formof water or steam can be feed to the block, possibly with at anincreased temperature and this moistener can, furthermore, containnutrients, fungicides or other additives which are preferably added inliquid form.

After the forming of the substrate blocks and the placement of these intrays 10 they are conveyed to a pricking out machine 4, where holes forthe receipt of cuttings are made. These cuttings can be placed manuallyor, as mentioned, with an automatic placing machine. Finally, the trays10 with substrate blocks are transferred to greenhouse tables 12 in agreenhouse.

In FIG. 2 the area with the forming chamber 18 is shown in more detail,where the infeed pipe 22 for loose substrate material is connected withthe forming chamber 18 per se. The paper width 16, from which an endlessair permeable pipe is formed, is indicated as a “shadow” at the infeedpipe 22 and is formed into a tube surrounding this. Immediately abovethe connection point for the paper width 16 a hose/pipe 20 for themoistener is led to into the infeed pipe 22. The amount of infedmoistener is controlled from a not shown control unit which,furthermore, comprises pumps and heating means. The infeed of themoistener is, normally, time controlled so that a pump is left runningor a valve is opened for a certain amount of time, which thus conveys ameasured amount for injection into the substrate block in question. Theamount of infed moistener is regulated by control weighing of a useableand filled “wet” tray 10, where the weight of this is compared to auseable and filled “dry” tray.

Under the forming chamber 18 a forwarding device 24 is indicated, whichpulls a new length from the paper pipe forward for filling and, at thesame time, pushes the filled paper casing down for cutting at anappropriate height. Subsequently, by using a displaceable dispositoryunit 26 a whole row of substrate blocks is placed in a suitable tray 10.

FIG. 3 indicates the profile of the forming chamber 18 and inside thisis shown a freely hanging hose 20 through which the moistener is infeed.The hose 20 can, in other embodiments of the machine 2, be replaced by astiff pipe which operates in the same way as the hose 20 shown here.When the forming chamber 18 is closed and an underpressure is createdthere is opened for the infeed of a “shot” of moistener, which isdistributed quickly in the substrate material because of the mentionedunderpressure. It is, furthermore, likely that the created underpressurecan neutralise mosquito larva, as they are expected to be killed bythis.

1. Method of producing growth substrate blocks for horticultural use,wherein a loose material from a supply of substantially loose substratematerial is fed into a forming chamber for compacting and, subsequently,the material is removed in compacted string form for the purpose offorming useable block bodies, by cutting the strings into blocks,wherein the method comprises a compulsory moistening of the strings,with a heated moisture medium prior to the cutting of the strings intoblocks and before the introduction of the blocks into a greenhousesystem, by establishing an infeed and treatment station from which theblocks successively are fed to the greenhouse system in a number ofrows, which pass an in-line mounting area for the cuttings in theblocks, after which the blocks with the mounted cuttings are transporteddirectly to the regular grow area(s) for the cuttings.
 2. Methodaccording to claim 1, wherein a moistener medium is fed to the materialin the compacting area during the shaping process, while the materialstill is loose and willingly is moistened during its movement towardsthe compacting area, and where the moistener in connection with theinfeed is distributed in the block in the forming chamber byunderpressure.
 3. Method according to claim 1, wherein the infeed ofmoisture medium takes in place in connection with a vertical inwardlydirected infeed of the infeed material to the forming chamber, whichequally is vertically oriented and from which the removed block materialis led directly into receiving cells in underlying, horizontallyconveyed mounting trays for delivery to the greenhouse.
 4. Methodaccording to claim 1, wherein the infed moisture medium has atemperature between 5° C. and 90° C.
 5. Method according to claim 1,wherein the mounting of the cuttings in prick openings in question isfully automated.
 6. Method according to claim 1, wherein one of perliteand clay are added to the substrate material in the block bodies. 7.Installation for producing growth substrate blocks for horticulturaluse, wherein the installation from a supply of substantially loosesubstrate material is fed loose material in a forming chamber forcompacting and subsequent removal of the material in a compacted stringform for the purpose of forming useable block bodies by cutting thestrings into blocks, wherein the installation comprises means forcompulsory moistening of the strings with a heated moisture mediumduring the compacting process in the forming chamber.
 8. Installationaccording to claim 7, wherein it comprises means for heating themoisture medium prior to the infeed of this to the block bodies. 9.Installation according to claim 7, wherein the means for compulsorymoistening are comprised of a pipe or a hose, which has been led intothe material infeed pipe prior to the infeed area for an air permeablepaper width, which surrounds already shaped strings, where said pipe orhose inside the infeed pipe extends to the area at the infeed end of theforming chamber.
 10. Installation according to claim 7, wherein meansfor supplying moisture medium are arranged in connection with n verticalinwardly directed infeed of the infeed material to the forming chamber,where the forming chamber is vertically oriented and from which theblock material with the use of placing means is led directly intoreceiving cells in underlying, horizontally conveyed receiving trays.11. Installation according to claim 7, further comprising means for afully automated mounting of cuttings in prick openings in the blockbodies.
 12. Method according to claim 1, wherein the infed moisturemedium has a temperature between 18° C. and 70° C.
 13. Method accordingto claim 1, wherein the substrate material is sphagnum.